Why 'more or less stopped using ISO'?

Started Feb 19, 2014 | Questions thread
Iliah Borg Forum Pro • Posts: 24,785
Re: Why 'more or less stopped using ISO'?

bobn2 wrote:

Iliah Borg wrote:

xpatUSA wrote:

bobn2 wrote:

D Cox wrote:

bobn2 wrote:

edhannon wrote:

There are three places that brightening can be applied:

  • With amplification between the sensor andq analog to digital conversion (e.g. Pentax *ist line)

That doesn't apply any 'brightening', it just makes the voltage representing a particular photo-electron count bigger.

Which will give a larger number when digitised, which will give a brighter image.

Well the depends entirely on the digitisation scale. Take the voltage and feed it into a 12 bit ADC it will give you a smaller number than if you feed it into a 14 bit ADC 9assuming the same reference voltage). All you are looking at is coding, not what is represented. What is represented is a count of photons, however you code it does not change what is represented.

Indeed, and this is no different to an obvious analogy of the same XYZ color being represented by different RGB numbers in different color spaces, so hopefully nobody will be arguing the toss about that!

1000mV are much brighter than 1V and ten times brighter than 100V.

And of course, had they used a current input ADC, you'd have to worry whether 1000mV was brighter than 1000mA, or a couple of raisins.

Abnormal normalization case.

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